Project 64 is the best N64 Emulator, flat-out, so it only makes sense for it to be ported over to homebrew. Wii64, and Not64 are both dead, and neither support USB controllers (specifically the Wii U GameCube adapter). Is porting Project 64 to homebrew something that you guys would want?

Wii64 is based on original mupen and doesn't contain many of the improvements in m64p.

That said to add some more points to what has been said, is there any vwii driver for the Gamecube Adapter yet? I don't know of any so I have some doubts that this would even work in any acceptable way without some huge additional effort.